It may be corny but I've always like 18-wheeler big rig transfer trucks ever since I was a kid in the 70's listening to CW Mcall sing Convoy. [link] and [link] . I saw this Kenworth pulling for the Thetford Porsche racing team at Laguna Seca.

Oh man, you're right...precious cargo. And, if you look right in front of the hood you can see the rear section of an identical truck about to come around the bend behind this truck. Two Porsche racing teams.